Test plug



FIG. 1 is a top perspective view of an exemplary test plug.

FIG. 2 is a bottom perspective view of the test plug of FIG. 1.

FIG. 3 is a side elevation view of the test plug of FIG. 1.

FIG. 4 is another side elevation view of the test plug of FIG. 1.

FIG. 5 is a top plan view of the test plug of FIG. 1; and,

FIG. 6 is a bottom plan view of the test plug of FIG. 1.

The broken lines depict the boundaries of the test plug and form no part of the claimed design. 

CLAIM The ornamental design for a test plug, as shown and described. 